As stored program-controlled switching systems have evolved, a wide variety of useful features have been developed to extend the communication capabilities such systems provide. Incoming calling line identification, a feature that displays the caller's number for incoming calls to a called customer station, allows selective acceptance of certain calls based on the calling number while other calls are either not answered or are routed to a message center. The feature is implemented by transmitting the calling line identification to the called customer station in a data message--for example, to an analog station during a silent interval between ringing or to an integrated services digital network (ISDN) station in the out-of-band D-channel used for call control signaling. Since customers typically remember only a few, frequently called telephone numbers, a related feature that provides a display of the caller name is substantially more useful to customers in deciding whether to accept a call. With a known call waiting feature where a caller-identifying data message is transmitted out-of-band, as for an ISDN station, a customer already engaged in an ongoing telephone conversation is informed of the caller identify for a second call that is coming in. Although such features provide customers with much greater control over their telephone communications, conventional analog stations, which represent a large majority of the customer stations in use today, are not equipped to either process or display data messages. In addition, modification of the normal human response of answering a ringing telephone, such that a customer glances at a display to determine caller identity before answering, is difficult, particularly for customers that use the features only infrequently.
In a call announcement arrangement which is the subject of the application Ser. No. 230,224, the calling party name is obtained from a database search and a text-to-speech unit generates speech signals, rather than a data message, for transmission to the called communication station. The calling party name is spoken at the station instead of being displayed. For a conventional analog station, the name is spoken after the called party has answered in response to ringing at the station but before a connection is completed to the caller. The called party accepts the call either by remaining off-hook or by transmitting a connection signal using, for example, flash or tone signaling. Although it is desirable to provide call announcement features to customers without requiring them to replace their analog stations, callers will experiennce increased answer delays waiting for their name to be announced to the called party, and for the call to thereafter be accepted. Such delays will result in a reduction in call completions since in some cases the caller will be unaware of the call announcement feature and may impatiently hang up. The delays can be reduced by making the call announcement before, rather than after, the call is answered. This would also make call rejection more convenient in some circumstances since there is need to answer the telephone to determine caller identity. However, no telephone station set of the prior art is capable of generating audible speech representing speech signals on the line while still in the on-hook state.